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From: Jens Axboe <axboe@kernel.dk>
To: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
	linux-block@vger.kernel.org
Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com,
	Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 18/18] io_uring: add io_uring_event cache hit information
Date: Wed, 23 Jan 2019 08:35:36 -0700	[thread overview]
Message-ID: <20190123153536.7081-26-axboe@kernel.dk> (raw)
In-Reply-To: <20190123153536.7081-1-axboe@kernel.dk>

Add hint on whether a read was served out of the page cache, or if it
hit media. This is useful for buffered async IO, O_DIRECT reads would
never have this set (for obvious reasons).

If the read hit page cache, cqe->flags will have IOCQE_FLAG_CACHEHIT
set.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c                 | 7 ++++++-
 include/uapi/linux/io_uring.h | 5 +++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index aa903fa902d5..a40b1af356e0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -561,11 +561,16 @@ static void io_fput(struct io_kiocb *req)
 static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
 {
 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
+	unsigned ev_flags = 0;
 
 	kiocb_end_write(kiocb);
 
 	io_fput(req);
-	io_cqring_add_event(req->ctx, req->user_data, res, 0);
+
+	if (res > 0 && (req->flags & REQ_F_FORCE_NONBLOCK))
+		ev_flags = IOCQE_FLAG_CACHEHIT;
+
+	io_cqring_add_event(req->ctx, req->user_data, res, ev_flags);
 	io_free_req(req);
 }
 
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 60b52c551c87..3b8d623031ad 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -71,6 +71,11 @@ struct io_uring_cqe {
 	__u32	flags;
 };
 
+/*
+ * io_uring_event->flags
+ */
+#define IOCQE_FLAG_CACHEHIT	(1 << 0)	/* IO did not hit media */
+
 /*
  * Magic offsets for the application to mmap the data it needs
  */
-- 
2.17.1


      parent reply	other threads:[~2019-01-23 15:36 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-23 15:35 [PATCHSET v7] io_uring IO interface Jens Axboe
2019-01-23 15:35 ` [PATCH 01/18] fs: add an iopoll method to struct file_operations Jens Axboe
2019-01-28 14:25   ` Christoph Hellwig
2019-01-28 16:13     ` Jens Axboe
2019-01-23 15:35 ` [PATCH 02/18] block: wire up block device iopoll method Jens Axboe
2019-01-23 15:35 ` [PATCH 03/18] block: add bio_set_polled() helper Jens Axboe
2019-01-28 14:26   ` Christoph Hellwig
2019-01-23 15:35 ` [PATCH 04/18] iomap: wire up the iopoll method Jens Axboe
2019-01-23 15:35 ` [PATCH 05/18] Add io_uring IO interface Jens Axboe
2019-01-28 14:57   ` Christoph Hellwig
2019-01-28 16:26     ` Jens Axboe
2019-01-28 16:34       ` Christoph Hellwig
2019-01-28 19:32         ` Jens Axboe
2019-01-28 18:25     ` Jens Axboe
2019-01-29  6:30       ` Christoph Hellwig
2019-01-29 11:58         ` Arnd Bergmann
2019-01-29 15:20           ` Jens Axboe
2019-01-29 16:18             ` Arnd Bergmann
2019-01-29 16:19               ` Jens Axboe
2019-01-29 16:26                 ` Arnd Bergmann
2019-01-29 16:28                   ` Jens Axboe
2019-01-29 16:46                     ` Arnd Bergmann
2019-01-29  0:47     ` Andy Lutomirski
2019-01-29  1:20       ` Jens Axboe
2019-01-29  6:45         ` Christoph Hellwig
2019-01-29 12:05           ` Arnd Bergmann
2019-01-31  5:11         ` Andy Lutomirski
2019-01-31 16:37           ` Jens Axboe
2019-01-23 15:35 ` [PATCH 06/18] io_uring: add fsync support Jens Axboe
2019-01-23 15:35 ` [PATCH 07/13] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-23 15:35 ` [PATCH 07/18] io_uring: support for IO polling Jens Axboe
2019-01-28 15:02   ` Christoph Hellwig
2019-01-28 16:46     ` Jens Axboe
2019-01-29  6:27       ` Christoph Hellwig
2019-01-29 13:20         ` Jens Axboe
2019-01-23 15:35 ` [PATCH 08/18] fs: add fget_many() and fput_many() Jens Axboe
2019-01-28 14:29   ` Christoph Hellwig
2019-01-28 16:48     ` Jens Axboe
2019-01-23 15:35 ` [PATCH 08/13] io_uring: add file set registration Jens Axboe
2019-01-23 15:35 ` [PATCH 09/13] io_uring: add submission polling Jens Axboe
2019-01-28 15:09   ` Christoph Hellwig
2019-01-28 17:05     ` Jens Axboe
2019-01-29  6:29       ` Christoph Hellwig
2019-01-29 13:21         ` Jens Axboe
2019-01-28 21:13   ` Jeff Moyer
2019-01-28 21:28     ` Jens Axboe
2019-01-23 15:35 ` [PATCH 09/18] io_uring: use fget/fput_many() for file references Jens Axboe
2019-01-23 15:35 ` [PATCH 10/13] io_uring: add io_kiocb ref count Jens Axboe
2019-01-23 15:35 ` [PATCH 10/18] io_uring: batch io_kiocb allocation Jens Axboe
2019-01-23 15:35 ` [PATCH 11/18] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2019-01-28 14:31   ` Christoph Hellwig
2019-01-28 16:54     ` Jens Axboe
2019-01-23 15:35 ` [PATCH 11/13] io_uring: add support for IORING_OP_POLL Jens Axboe
2019-01-23 15:35 ` [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-23 15:35 ` [PATCH 12/13] io_uring: allow workqueue item to handle multiple buffered requests Jens Axboe
2019-01-23 15:35 ` [PATCH 13/18] io_uring: add file set registration Jens Axboe
2019-01-23 15:35 ` [PATCH 13/13] io_uring: add io_uring_event cache hit information Jens Axboe
2019-01-23 15:35 ` [PATCH 14/18] io_uring: add submission polling Jens Axboe
2019-01-23 15:35 ` [PATCH 15/18] io_uring: add io_kiocb ref count Jens Axboe
2019-01-23 15:35 ` [PATCH 16/18] io_uring: add support for IORING_OP_POLL Jens Axboe
2019-01-23 15:35 ` [PATCH 17/18] io_uring: allow workqueue item to handle multiple buffered requests Jens Axboe
2019-01-23 15:35 ` Jens Axboe [this message]

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